Bilstein B6 Ride Quality

[MidwayJ]

Here's the setup on my 2019 GT 400A: PP1 struts, Bilstein B6 rear shocks, BMR SP763 minimum drop springs, PP1 toe links, and BMR cradle lockouts.

I expected the Bilstein B6 shocks to feel firmer, especially over sharp bumps and rough patches at low speeds. This is the case but the difference is not significant. It's fine, for example, going over most railroad tracks on a level surface.

I ALSO expected a more controlled ride overall, but I'm disappointed. When bumps are fairly big or the road is undulating, it feels like the whole car follows the up and down contours of the road too much instead of the suspension absorbing anything. When the road is built up at railroad tracks (like a mini "hill") the rear feels like it wants to jump over it (and would if I went fast enough ). The bottom line is the car's reaction to up and down contours of significance (even if "smooth" rather than sharp) feels exaggerated and disrupts control of the car. Any ideas?

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[Roadway 5.0]

I run B6 shocks and struts on Ford X Springs.

Make sure your rear bump-stops are cut a bit to accommodate your minimum drop springs.

What wheels and tires are you running? Outdoor temps?

I don’t have a lick of disruption with my setup and the ride is pleasantly firmer and more controlled. The only time the car is a bit hyper is at 15-20mph — only present with my 30 series MPS4S tires when close to their 45 degree ambient temperature limit.

 

[MidwayJ]

I run B6 shocks and struts on Ford X Springs.

Make sure your rear bump-stops are cut a bit to accommodate your minimum drop springs.

What wheels and tires are you running? Outdoor temps?

I don’t have a lick of disruption with my setup and the ride is pleasantly firmer and more controlled. The only time the car is a bit hyper is at 15-20mph — only present with my 30 series MPS4S tires when close to their 45 degree ambient temperature limit.

My understanding is the installer cut 1/4 inch off the bump stops. The springs lower the car 1/2 inch in the rear.

I'm running General UHP all seasons 275/40r19 on 19x9.5 all around. Same setup I had before the changes a few months ago. Temperatures have mostly ranged from 40s to 70s. What I described seems to have gotten worse since the changes were first made, or maybe it's just bothering me more.

 

[Brian@BMVK]

Here's the setup on my 2019 GT 400A: PP1 struts, Bilstein B6 rear shocks, BMR SP763 minimum drop springs, PP1 toe links, and BMR cradle lockouts.

I expected the Bilstein B6 shocks to feel firmer, especially over sharp bumps and rough patches at low speeds. This is the case but the difference is not significant. It's fine, for example, going over most railroad tracks on a level surface.

I ALSO expected a more controlled ride overall, but I'm disappointed. When bumps are fairly big or the road is undulating, it feels like the whole car follows the up and down contours of the road too much instead of the suspension absorbing anything. When the road is built up at railroad tracks (like a mini "hill") the rear feels like it wants to jump over it (and would if I went fast enough ). The bottom line is the car's reaction to up and down contours of significance (even if "smooth" rather than sharp) feels exaggerated and disrupts control of the car. Any ideas?

You're actually feeling what more damping control is. Increased rebound damping doesn't let the sprung mass rise as easily when going over road contours, so it will feel more hunkered down into the road.

What you're describing sounds to me more like one or more of the following things:
1. It's riding on the bumpstops
2. Your alignment is out of whack
3. Your tire pressures may be off
4. Unclocked suspension bushings after lowering

 

[Roadway 5.0]

My understanding is the installer cut 1/4 inch off the bump stops. The springs lower the car 1/2 inch in the rear.

I'm running General UHP all seasons 275/40r19 on 19x9.5 all around. Same setup I had before the changes a few months ago. Temperatures have mostly ranged from 40s to 70s. What I described seems to have gotten worse since the changes were first made, or maybe it's just bothering me more.

Double check that the bumpstops are cut for sure — about 3/4”cut should be your goal.

Also check your alignment; for stability you need toe-in on the rear wheels; lowering the car pushes them to toe out.

Lastly, pump up those all season tires a couple of psi and see if that helps.

Overall, the spring rates you chose, Bilsteins, and plushy tall all seasons should give a smooth ride...maybe not super firm with those tires, but certainly smooth.

 

[shogun32]

find some climbing/decending 4-leaf interchanges and try to feel what the car is doing when you bend it into the curve and when you come out of the curve. Do you get multiple oscillations, or just 1 as the weight moves around? Ideally you get 1 or 1.5.

 

[MidwayJ]

You're actually feeling what more damping control is. Increased rebound damping doesn't let the sprung mass rise as easily when going over road contours, so it will feel more hunkered down into the road.

What you're describing sounds to me more like one or more of the following things:
1. It's riding on the bumpstops
2. Your alignment is out of whack
3. Your tire pressures may be off
4. Unclocked suspension bushings after lowering

I suppose 1 and 4 are possibilities. The car tracks straight with no uneven tire wear. Tire pressure is currently 32-33 when warm.

 

[MidwayJ]

Double check that the bumpstops are cut for sure — about 3/4”cut should be your goal.

Also check your alignment; for stability you need toe-in on the rear wheels; lowering the car pushes them to toe out.

Lastly, pump up those all season tires a couple of psi and see if that helps.

Overall, the spring rates you chose, Bilsteins, and plushy tall all seasons should give a smooth ride...maybe not super firm with those tires, but certainly smooth.

Thanks. I'll check the alignment for the rear toe in. And the bump stops. Anyone know what they measure uncut? And add air to the tires. They seem to gone down 2-3 psi since the last time I put air in them.

 

[Roadway 5.0]

I suppose 1 and 4 are possibilities. The car tracks straight with no uneven tire wear. Tire pressure is currently 32-33 when warm.

Aim for 36psi warm, especially with all-seasons. My winters get BAD flatspots every night if I have them too low on air — you can see the same with some brands all seasons.

 

[Brian@BMVK]

I suppose 1 and 4 are possibilities. The car tracks straight with no uneven tire wear. Tire pressure is currently 32-33 when warm.

Was the car aligned after the springs and lockout? Needs to be done after the bushings get clocked. Just because it tracks straight doesn't mean it's got a good street alignment.

 

[MidwayJ]

Was the car aligned after the springs and lockout? Needs to be done after the bushings get clocked. Just because it tracks straight doesn't mean it's got a good street alignment.

It wasn't. Guy who installed said I might not need it because of the minimal drop. I decided to watch tire wear, etc. and never got it aligned. Sounds like that wasn't a good idea. I didn't realize it could effect the ride.

 

[ctandc72]

Try tire pressure first. Cars can be REALLY Sensitive to tire pressure. Even a small difference. I'll never forget picking up an almost free Miata to flip ("blown head gasket" was a cracked radiator hose - no, not kidding. Got it for $100). Got it running good, it had brand new tires on it from the previous owner. It was downright SCARY. Twitchy, the rear wanted to come around. Checked the tire pressure. Pressure was almost 40psi. Recommended pressure was under 30 psi for that little go cart. Lowered the tire pressure to spec and I literally couldn't believe the difference.

 

[MidwayJ]

find some climbing/decending 4-leaf interchanges and try to feel what the car is doing when you bend it into the curve and when you come out of the curve. Do you get multiple oscillations, or just 1 as the weight moves around? Ideally you get 1 or 1.5.

I'll give it a try. I've been generally happy with the handling as the rear feels more planted than stock.

 

[Brian@BMVK]

It wasn't. Guy who installed said I might not need it because of the minimal drop. I decided to watch tire wear, etc. and never got it aligned. Sounds like that wasn't a good idea. I didn't realize it could effect the ride.

Unfortunately, no. It does not take that much ride height change to throw it off significantly, and there's a good chance that the lockout alone did enough to necessitate one.

Definitely make an appointment to get the bushings clocked while on the rack, and then aligned after. The ones circled in blue are the ones to get (on both sides).

 

[MidwayJ]

Unfortunately, no. It does not take that much ride height change to throw it off significantly, and there's a good chance that the lockout alone did enough to necessitate one.

Definitely make an appointment to get the bushings clocked while on the rack, and then aligned after. The ones circled in blue are the ones to get (on both sides).

Thanks for the info on the bushings. Between this and tire pressure it's good to know things can be done to make changes for the better.

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